Streamable HTTP resumability + redelivery + SSE polling via server-side disconnect (#1077)

Co-authored-by: Stephen Halter <halter73@gmail.com>

src/ModelContextProtocol.Core/Client/HttpClientTransportOptions.cs

@@ -108,4 +108,31 @@ public sealed class HttpClientTransportOptions
     /// Gets sor sets the authorization provider to use for authentication.
     /// </summary>
     public ClientOAuthOptions? OAuth { get; set; }
+
+    /// <summary>
+    /// Gets or sets the maximum number of consecutive reconnection attempts when an SSE stream is disconnected.
+    /// </summary>
+    /// <value>
+    /// The maximum number of reconnection attempts. The default is 2.
+    /// </value>
+    /// <remarks>
+    /// When an SSE stream is disconnected (e.g., due to a network issue), the client will attempt to
+    /// reconnect using the Last-Event-ID header to resume from where it left off. This property controls
+    /// how many reconnection attempts are made before giving up.
+    /// </remarks>
+    public int MaxReconnectionAttempts { get; set; } = 2;
+
+    /// <summary>
+    /// Gets or sets the default interval at which the client attempts reconnection after an SSE stream is disconnected.
+    /// </summary>
+    /// <remarks>
+    /// <p>
+    /// The default value is 1 second.
+    /// </p>
+    /// <p>
+    /// If the server sends a message specifying a different reconnection interval, that new value will be used for all
+    /// subsequent reconnection attempts for that stream.
+    /// </p>
+    /// </remarks>
+    public TimeSpan DefaultReconnectionInterval { get; set; } = TimeSpan.FromSeconds(1);
 }